A loon's beak, legs, and feet stay warm when exposed to cold water
because the Loon's beak is made of the same kind of tissue as our finger
nails, without a blood supply that could get cooled by the air and then
travel through the rest of the body. The legs and feet have a much
smaller blood flow than our legs and feet. In the loon, blood flowing
from the cold feet back up into the warm body gets heated as it travels
in vessels right next to the hot blood.